Resilient outboard motor mounting



E. RosE RESILIENT oUTBoARD MToR MOUNTING Filed July 11, 1955 June 16,1959 INVENToR. 506A@ R05@ A TOR/vars United States Patent RESILIENTOUTBOARD MOTOR MOUNTING Edgar Rose, Oshkosh, Wis., assignor to KekhaeferCorporation, Cedarburg, Wis., a corporation of Wisconsin ApplicationJuly 11, 1955, Serial No. 520,991

4 Claims. (Cl. 115--18) This invention relates to outboard motors andparticularly to the resilient support of the engine and underwaterpropeller assembly joined by the drive shaft as a rigid assemblycomprising the power unit.

According to the invention, a cowl structure is exteriorly supported bya clamp bracket assembly for pivotal steering movement on a verticalaxis. The power unit is resiliently mounted in a cowl structure with thedrive shaft housing projecting from a downward opening in the cowl todispose the propeller underwater. The weight of the power unit isconcentrated in the engine and the weight of the unit is resilientlysupported at a point considerably below the engine so that a series ofextremely resilient stabilizers located between the engine and cowl andallowing oscillation of the unit about said point are adequate tomaintain the power unit upright and secure the unit against the momentwhich is set up by the thrust of the propeller.

An object of the invention is to provide the improved resilient supportof the power unit to isolate the vibration of the power unit from theboat and reduce noise.

Another object is to support the power unit by resilient means with aminimum of loading effected by the thrust of the propeller.

The drawings furnished herewith illustrate the best mode of carrying outthe invention as presently contemplated and set forth hereinafter.

In the drawings:

Figure 1 is a side elevation of an outboard motor with parts thereofbroken away and sectioned to show the support of the motor unit withinthe cowl;

Fig. 2 is a section taken on line 2 2 of Figure l;

Fig. 3 is a section taken on line 3-3 of Figure 1; and

Fig. 4 is an enlarged sectional view of the forward resilient elementlocated within the upper portion of the cowl to stabilize the motor unitas shown in Figure l.

The outboard motor shown in the drawings includes the engine 1 showndiagrammatically and as disposed within the cowl structure 2 formed bythe upper and lower cowl members 3 and 4, respectively.

The drive shaft 5 extending upwardly from the lower underwater gear case6 to engine 1 is enclosed by the drive shaft housing 7 which supportsthe engine. Housing 7 connects engine 1 and gear case 6 to comprise thepower unit 8, which is resiliently supported as a rigid assembly.

The propeller 9 is driven by engine 1 through shaft 5 and the geartransmission, not shown, of gear case 6 and is disposed rearwardly ofthe gear case and immediately beneath the flat anti-cavitation plate 10extending horizontally between the lower end of housing 7 and the upperend of gear case 6. The upper end of shaft 5 is connected to the lowerend 11 of the vertical crankshaft of engine 1;

Engine 1 is seated on the llat upper face of housing 7 to discharge theengine exhaust into the enlarged, open upper end of the housing. Theexhaust passing through housing 7 which generally diminishes incross-section is discharged through the nozzle 12 located beneath and atthe rear of plate 10 and opening rearwardly into the propeller slipstream.

The bracket member 13 which is adapted to be secured to the transom of aboat, not shown, pivotally carries the vertically spaced lugs 14projecting forwardly from the lower portion of cowl member 4 forrelative movement of cowl structure 2 on a vertical axis. The lowerportion of cowl member 4 is of dimensions generally correspondinglylarger than housing 7 and encloses the housing with adequate clearancetherebetween for the vibration of the power unit 8 within the cowlstructure, as will be described.

The resilient cushion 15 is seated on the narrow shelf 16 extending atthe front of and across the lower opening of cowl member I4 from whichhousing 7 projects downwardly.

The forward bracket 17 of housing 7 rests on cushion 15 and is locatedbeneath engine 1 to support substantially the entire weight of the powerunit 8 within cowl structure 2. The power unit 8 is maintained uprightby the series of L-shaped resilient elements 18 having correspondingends carried in the fixtures 19 secured to engine 1 and correspondingother ends fixed in the sockets 20 formed in the bosses 21 locatedaround the inner, upper periphery of cowl member 4. The elements 18 andtheir mountings are similar to that described and claimed in thecopending application of the present inventor, filed March 14, 1955,Serial No. 494,216.

Elements 18 are horizontally spaced relative to each other and about theupper periphery of cowl member 4 to position engine 1 centrally withinthe cowl and to yield to the vibration of the engine which causes thevibration of the entire power unit 8.

The vibration of the power unit 8 includes rotational oscillation on avertical axis which is due to the torque reaction of the engine to eachtorque impulse applied by the engine to the vertical shaft 5 and thevibration of engine 1 which is due to the unbalanced forces set up bythe moving parts of the engine and occurs principally in the horizontaldirection which is normal to the axis of the engine crankshaft.

According to the present invention the vertical support of the powerunit well below the engine and the considerable lateral or horizontalmovement allowed the engine in the cowl permits most vibration todissipate itself without transmission to the boat, and the securement ofthe power unit by cushion 15 may be adequately provided withoutrestraining the vibration.

Cushion 15 may be bonded between shelf 16 and the bracket 17 which mayfurther include the projection V22 extending downwardly into thecushion. Cushion 15 should be reasonably lirrn to support the power unitbut with some resilience to absorb the small pulsations in the thrust ofthe propeller which is due to the unevenness of the power outputreferred to above in connection with the torque reaction of the engine.

Since the weight of the power unit is carried by cushion 15, vibrationof power unit 8 is essentially limited to movement around the flexibleconnection provided by cushion 15 between housing 7 and cowl member 4.With the connection referred to located as far below engine 1 aspracticable, the movement of the engine oc` curring theoretically in aat arc is then substantially horizontal and coincident with its naturalvibration.

Elements 1S are of a free length to allow considerable movement ofengine 1 in the cowl structure 2 and tion is necessarily absorbed by thecompression of the elements 13 and transmitted through cowl structure 2and bracket 13 to the boat.

According further to the invention the flexible connection referred tois located as low as practicable so that the thrust of the propeller ineither the forward or reverse direction does not appreciably load thecorresponding elements 13 and adversely affect the isolation of thevibration of the power unit. The thrust referred to sets up a moment ortendency toward rotational move ment of the power unit on a transverseaxis so that opposite horizontal loads are applied to cushion 15 and theforward or rearward-most elements 1S. With the cushion 15 located asnear as practicable to propeller 9 and as remote as practicable fromelements 18, a relatively minor proportion of the thrust load is appliedto the elements 18 and the major thrust load applied to cushion 15 doesnot in any material way increase the resistance of the cushion to thevibration of the power unit 8 about the flexible connection formed bythe cushion. The large amplitude of vibration of the power unitoccurring particularly at low engine speeds is readily absorbed by theresilience of elements 18, and is accommodated by the clearance betweenthe power unit and the interior ol' cowl structure 2.

Various modes of carrying out the invention are contemplated as withinthe scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

I claim:

l. In an outboard motor, a bracket to be attached to a boat, a cowlstructure having a lower opening and sup ported `by said bracket for thepivotal movement of the cowl structure on a vertical axis, a powerassembly cornprising an engine and underwater propeller unit and anintermediate hollow housing rigidly connecting said engine and propellerunit, the weight or" said engine being the greater part of the weight ofthe power assembly, the lower portion of said cowl structure and saidhousing having a flexible connection supporting the power assembly withthe engine disposed in the upper portion of the cowl structure and withthe housing extending downwardly therefrom and through the openingthereof, and horizontally spaced resilient elements disposed betweensaid engine and cowl structure and positioning the engine therein, saidsupporting connection being below and relatively remote from the enginewhereby normal horizontal vibration of the engine substantiallycoincides with the movement of the power assembly about said flexibleconnection permitted by said resilient elements, and said flexibleconnection being relatively adjacent to 'the underwater propeller unitwhereby the thrust of the propeller unit is in greater part directedagainst and carried by the exible connection and said resilient elementsare subject to nominal loading and relatively unaffected by the thrustof the propeller unit.

2. In an outboard motor, a bracket to be attached to a boat, a cowlstructure having a lower opening and supported by said bracket for thepivotal movement of the cowl structure on a vertical axis, a powerassembly cornprising an engine and underwater propeller unit and anintermediate hollow housing rigidly connecting said engine and propellerunit, the weight of said engine being the greater part of the weight ofthe power assembly, the -lower portion of said cowl structure and saidhousing having a exible connection supporting the power assembly withthe engine disposed in the upper portion of the cowl structure and withthe housing extending downwardly therefrom and through the openingthereof, and

4 t horizontally spaced resilient elements comprising L- shaped elementsseated in corresponding abutments carried respectively vby the engineand supporting cowl structure and positioning the engine within the cowlstructure, said supporting connection being below and relatively remotefrom the engine whereby normal horizontal vibration of the enginesubstantially coincides with the movement of the power assembly aboutsaid flexible connection permitted by said resilient elements, and saidflexible connection being relatively adjacent to the underwaterpropeller' unit whereby the thrust of the propeller unit is in greaterpart directed against and carried by the exible connection and saidresilient elements are subject to nominal loading and relativelyunaffected by the thrust of the propeller unit.

3. In an outboard motor, a transom mounting including a bracket, asupporting structure pivotally connected to the bracket and therebyproviding a vertical steering axis for the outboard motor, a powerassembly comprising an engine and an underwater propeller unit and anintermediate hollow housing rigidly connecting said engine and saidpropeller unit, the weight of said engine being the greater part of theweight of the assembly and being positioned generally to the rear ofsaid steering axis so that the vertical rotational oscillation axis ofthe engine is disposed rearwardly of said steering axis, meanspositioning said power assembly with relation to the supportingstructure and comprising a plurality of resilient elements spacedcircumferentially of said assembly and having opposed abutments carriedrespectively by said engine and said supporting structure and adapted toabsorb the torque forces of said engine about said oscillation axis, andresilient cushion means on said supporting structure spacedsubstantially ybelow said resilient elements and engaging saidintermediate housing and vertically interlocked therewith to support theweight of the power assembly, said cushion means receiving the greaterpart of the thrust of said propeller unit with the resilient elementsbeing subject only to nominal propeller thrust loading whereby thevibratory movement of the power assembly allowed by said elements issubstantially unaffected by the thrust of the propeller unit.

4. In an outboard motor, a transom mounting including a bracket, asupporting structure pivotally connected to the lbracket and therebyproviding a vertical steering axis for the outboard motor, a powerassembly comprising an engine and an underwater propeller unit and anintermediate hollow housing rigidly connecting said engine and saidpropeller unit, the weight of said engine being the greater part of theweight of the assembly and being positioned generally to the rear ofsaid steering axis so that the vertical rotational oscillation axis ofthe engine is disposed rearwardly of said steering axis, meanscornprising a plurality of L-shaped resilient elements spacedcircumferentially of said assembly and having opposed abutments disposednormal to each other and carried respectively by said engine and saidsupporting structure and adapted to absorb torque forces of said engineabout said oscillation axis, and additional cushion means spacedsubstantially below said resilient elements and disposed betweeen saidassembly and said structure to effectively provide for transmission ofthe propeller thrust to the boat.

References Cited in the le of this patent UNITED STATES PATENTS

